The present invention relates to a vacuum cleaning tool for a vacuum cleaner, including a suction or intake opening and a brush roller that is disposed in the intake opening and is rotatably driven by an air turbine that in turn is driven by an intake air flow.
During the vacuum cleaning of textile floor coverings and smooth floor surfaces, the flow energy of the inflowing intake air stream is frequently inadequate for loosening dirt particles that adhere to the surface that is to be cleaned. Therefore, especially when cleaning textile floor coverings, a rotatably driven brush roller is provided in the intake opening. With respect to a textile floor covering, the rotating brush roller also serves to again raise nap or pile that has been matted or otherwise pressed down, as a result of which in addition to achieving an improved access to the dirt particles that are deposited in the base of the carpet nap, an improved visual effect is also achieved.
The drive for the rotating brush roller is effected via an air turbine that in turn is driven by the intake air stream that is flowing through the vacuum cleaning tool. By means of a belt drive, the rotation of the turbine wheel is transferred to the rotatably mounted brush roller, accompanied by simultaneous reduction of the speed. The blade arrangement of the turbine wheel is closed, in other words, adjacent blades define a closed space that is open only toward the flow-in direction of the intake air stream, but is closed relative to the axis of rotation of the turbine. The intake air stream that enters is deflected in the base of the blades and undergoes turbulence in the turbine chamber. Due to different floor surfaces such as smooth floors or textile floor coverings having different nap heights and densities, and due to the back and forth operating movements as well as a restriction of the intake air stream that frequently occurs from the dust filter getting loaded with dirt, the intake air stream that drives the turbine wheel, and hence also the torque and speed of the brush roller, fluctuate greatly.
It is therefore an object of the present invention to provide a vacuum cleaning tool of the aforementioned general type that provides an adequately high torque and speed at the brush roller, even when fluctuations of the intake air stream are encountered.